Two car bombs exploded in a Turkish town near the border with Syria today, killing at least 40 people and injuring 100 others.

Interior minister Muammer Guler said the explosions hit the town of Reyhanli, just across the border from Syria's Idlib province. One of the car bombs exploded outside the town hall while the other went off outside the post office, he said.

Suspicion immediately fell on Syria, but there was no immediate confirmation of its involvement. Turkey, which shares a more than 500-mile border with Syria, has been a crucial supporter of the Syrian rebel cause and Ankara has allowed its territory to be used as a logistics base and staging centre for Syrian insurgents.

Health minister Mehmet Muezzinoglu said at least 15 ambulances were helping the injured.

The frontier area has seen heavy fighting. In February, a car bomb exploded at a border crossing with Turkey in Idlib, killing 14. Turkey's interior minister has blamed Syria's intelligence agencies and its army for involvement.

Four Syrians and a Turk are in custody in connection with the February 11 attack at the Bab al-Hawa frontier post. No one has claimed responsibility, but a Syrian opposition faction accused the Syrian government of the bombing, saying it narrowly missed 13 leaders of the group.

In that bombing, most of the victims were Syrians who had been waiting in an area straddling the frontier for processing to enter Turkey.

Tensions flared between the Syrian regime and Turkey after shells fired from Syria landed on the Turkish side, prompting Germany, the Netherlands and the United States to send two batteries of Patriot air defence missiles each to protect their Nato ally.